This is because:
* They are extremely diverse: There are over 30,000 species of bony fishes, which makes them the largest class of vertebrates.
* They inhabit a wide range of environments: They can be found in freshwater, saltwater, and even brackish environments, from the shallows to the deepest parts of the ocean.
* They exhibit incredible adaptations: They have evolved a wide array of adaptations that allow them to thrive in different environments, including specialized fins, scales, and respiratory systems.
Within Osteichthyes, the two major groups are:
* Actinopterygii (ray-finned fishes): This group is the most diverse and includes familiar species like tuna, salmon, and goldfish. They have fins supported by bony rays.
* Sarcopterygii (lobe-finned fishes): This group is less diverse and includes lungfishes and coelacanths. They have fleshy fins with a bony internal skeleton.
While both groups are important, Actinopterygii (ray-finned fishes) are the most abundant and diverse group within the Osteichthyes class. They are responsible for the majority of the diversity and abundance of fishes we see today.
